Parasitemia is the quantitative content of

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

s in the

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...

. It is used as a measurement of parasite load in the organism and an indication of the degree of an active

parasitic infection A parasitic disease, also known as parasitosis, is an infectious disease caused by parasites. Parasites are organisms which derive sustenance from its host while causing it harm. The study of parasites and parasitic diseases is known as parasitolog ...

. Systematic measurement of parasitemia is important in many phases of the assessment of disease, such as in

diagnosis Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engin ...

and in the follow-up of therapy, particularly in the chronic phase, when cure depends on ascertaining a parasitemia of zero. The methods to be used for quantifying parasitemia depends on the parasitic species and its life cycle. For instance, in

malaria Malaria is a mosquito-borne infectious disease that affects humans and other animals. Malaria causes symptoms that typically include fever, tiredness, vomiting, and headaches. In severe cases, it can cause jaundice, seizures, coma, or death. S ...

, the number of blood-stage parasites can be counted using an

optical microscope The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of microsco ...

, on a special thick film (for low parasitemias) or thin film blood smear (for high parasitemias). The use of

molecular biology Molecular biology is the branch of biology that seeks to understand the molecular basis of biological activity in and between cells, including biomolecular synthesis, modification, mechanisms, and interactions. The study of chemical and physi ...

techniques, such as PCR has been used increasingly as a tool to measure parasitemia, especially in patients in the chronic phase of disease. In this technique, blood samples are obtained from the patient, and specific DNA of the parasite is extracted and amplified by PCR.

References

External links

Parasitology Abnormal clinical and laboratory findings for blood {{Med-sign-stub